This invention relates generally to selectively encodable systems for establishing communication between two parties under the independent control of such parties.
In the prior art, various radio-type signalling systems have been disclosed for various purposes. Reference may be made to the following as showing various systems.
U.s. pat. No. 2,845,619 to Robert E. Rawlings 7-29-58 PA1 U.s. pat. No. 3,440,635 to H. B. Hull 4-22-69 PA1 U.s. pat. No. 3,473,127 to R. E. Williams et al 10-14-69 PA1 U.s. pat. No. 3,478,344 to F. K. Switzgebel et al 11-11-69 PA1 U.s. pat. No. 3,588,858 to Thomas P. Demuth 6-28-71 PA1 U.s. pat. No. 3,609,741 to Wendell S. Miller 9-28-71 PA1 U.s. pat. No. 3,618,059 to Milton F. Allen 11-2-71 PA1 U.s. pat. No. 3,796,958 to Paul M. Johnston et al 3-12-74
The patents disclose various modes of radio communication for different purposes which may be briefly summarized as follows.
Rawlings discloses encoded transponder signals in a radar system, and Miller discloses baggage protection transponding apparatus.
Hull discloses a personal broadcasting device for direction finding in police work and the like.
Williams discloses a broadband detector for covert radio frequency broadcasts.
Switzgebel discloses a central station communication with portable remote transceivers.
Demuth discloses a portable transmitter with automatically actuated means to signal a mishap to the user.
Allen generally discloses a magnet-controlled switch in an alarm system for protecting articles, and Johnston discloses particular transmitter circuitry.
Although such devices have been suggested, none are uniquely constructed and interrelated to permit a unique matching of parties based upon selective actuation of the units by the two parties involved. Thus, in various situations, it would be highly desirable if a party could transmit to a total class of different categories or subclasses in accordance with any one of a plurality of categories and with those within a particular category notified and capable of responding automatically or selectively.
Thus, the prior art does not suggest a personal selection and contact means from a category of persons which is provided by the structure and functional results and advantages of the present invention, which is fully set forth in the following description.